我通常尽量避免子类化，但如果你已经:

// add a property 
@property (nonatomic) UIEdgeInsets edgeInsets;

// and override:

- (CGRect)textRectForBounds:(CGRect)bounds
{
    return [super textRectForBounds:UIEdgeInsetsInsetRect(bounds, self.edgeInsets)];
}

- (CGRect)editingRectForBounds:(CGRect)bounds
{
    return [super editingRectForBounds:UIEdgeInsetsInsetRect(bounds, self.edgeInsets)];
}

@IBInspectable， @IBDesignable swift类怎么样?

@IBDesignable
class TextField: UITextField {
    @IBInspectable var insetX: CGFloat = 6 {
       didSet {
         layoutIfNeeded()
       }
    }
    @IBInspectable var insetY: CGFloat = 6 {
       didSet {
         layoutIfNeeded()
       }
    }

    // placeholder position
    override func textRectForBounds(bounds: CGRect) -> CGRect {
        return CGRectInset(bounds , insetX , insetY)
    }

    // text position
    override func editingRectForBounds(bounds: CGRect) -> CGRect {
        return CGRectInset(bounds , insetX , insetY)
    }
}

你会在你的故事板中看到这个。

更新- Swift 3

@IBDesignable
class TextField: UITextField {
    @IBInspectable var insetX: CGFloat = 0
    @IBInspectable var insetY: CGFloat = 0

    // placeholder position
    override func textRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.insetBy(dx: insetX, dy: insetY)
    }

    // text position
    override func editingRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.insetBy(dx: insetX, dy: insetY)
    }
}

Swift 5版本的克里斯托弗的答案与额外的用法示例

import UIKit

private class InsetTextField: UITextField {
    var insets: UIEdgeInsets

    init(insets: UIEdgeInsets) {
        self.insets = insets
        super.init(frame: .zero)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("not intended for use from a NIB")
    }

    // placeholder position
    override func textRect(forBounds bounds: CGRect) -> CGRect {
         return super.textRect(forBounds: bounds.inset(by: insets))
    }
 
    // text position
    override func editingRect(forBounds bounds: CGRect) -> CGRect {
         return super.editingRect(forBounds: bounds.inset(by: insets))
    }
}

extension UITextField {

    class func textFieldWithInsets(insets: UIEdgeInsets) -> UITextField {
        return InsetTextField(insets: insets)
    }

}

用法:-

class ViewController: UIViewController {

  private let passwordTextField: UITextField = {

        let textField = UITextField.textFieldWithInsets(insets: UIEdgeInsets(top: 10, left: 15, bottom: 10, right: 15))
     // ---
   
        return textField
    }()

}

我发现了罗伯托发布的选项。buratti是最快的解决方案，这里是Swift:

let leftView = UIView(frame: CGRect(x: 0, y: 0, width: 10, height: textField.frame.size.height))
leftView.backgroundColor = textField.backgroundColor
textField.leftView = leftView
textField.leftViewMode = UITextField.ViewMode.always

如果你有一个明确的按钮，接受的答案将不适合你。我们还应该警惕苹果在未来通过调用super来改变事情。

因此，为了确保文本不会与清除按钮重叠，让我们先从super中获取“默认”值，然后根据需要进行调整。

这段代码将在文本框的顶部、左侧和底部添加一个10px的insets:

@interface InsetTextField : UITextField

@end


@implementation InsetTextField

// Placeholder position
- (CGRect)textRectForBounds:(CGRect)bounds {
    CGRect rect = [super textRectForBounds:bounds];
    UIEdgeInsets insets = UIEdgeInsetsMake(10, 10, 10, 0);

    return UIEdgeInsetsInsetRect(rect, insets);
}

// Text position
- (CGRect)editingRectForBounds:(CGRect)bounds {
    CGRect rect = [super editingRectForBounds:bounds];
    UIEdgeInsets insets = UIEdgeInsetsMake(10, 10, 10, 0);

    return UIEdgeInsetsInsetRect(rect, insets);
}

// Clear button position
- (CGRect)clearButtonRectForBounds:(CGRect)bounds {
    CGRect rect = [super clearButtonRectForBounds:bounds];

    return CGRectOffset(rect, -5, 0);
}

@end

注意:UIEdgeInsetsMake接受参数的顺序是:上，左，下，右。

下面是在Swift 3中编写的相同子类UITextField。它与之前的Swift版本有很大的不同，正如你将看到的:

import UIKit

class MyTextField: UITextField
    {
    let inset: CGFloat = 10

    // placeholder position
    override func textRect(forBounds bounds: CGRect) -> CGRect
        {
        return bounds.insetBy(dx: inset, dy: inset)
        }

    // text position
    override func editingRect(forBounds bounds: CGRect) -> CGRect
        {
        return bounds.insetBy(dx: inset, dy: inset)
        }

    override func placeholderRect(forBounds bounds: CGRect) -> CGRect
        {
        return bounds.insetBy(dx: inset, dy: inset)
        }
    }

顺便说一句，如果你只想控制一侧的插入，你也可以像下面这样做。如果你把一个图像放在UITextField的顶部，但你想让它在用户看来是在文本框中，那么这个只调整左边插图的特殊例子就很方便了:

    override func editingRect(forBounds bounds: CGRect) -> CGRect
        {
        return CGRect.init(x: bounds.origin.x + inset, y: bounds.origin.y, width: bounds.width - inset, height: bounds.height)
        }